Diagnostic Detection of Human Lung Cancer-Associated Antigen Using a Gold Nanoparticle-Based Electrochemical Immunosensor

• Published in: Analytical chemistry (Washington) Vol. 82; no. 14; pp. 5944 - 5950
• Main Authors: Ho, Ja-an Annie, Chang, Heng-Chia, Shih, Neng-Yao, Wu, Li-Chen, Chang, Ying-Feng, Chen, Chii-Chang, Chou, Chien
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.07.2010
• Subjects: Analytical chemistry; Antibodies, Monoclonal - chemistry; Antibodies, Monoclonal - immunology; Antigens; Antigens, Neoplasm - analysis; Antigens, Neoplasm - immunology; Biomarkers; Biosensing Techniques - methods; Cells; Chemistry; Electrocatalysis; Electrochemical methods; Electrochemical Techniques - methods; Electrodes; Exact sciences and technology; General, instrumentation; Gold - chemistry; Head & neck cancer; Humans; Immunology; Lung cancer; Lung Neoplasms - diagnosis; Metal Nanoparticles - chemistry; Phosphopyruvate Hydratase - analysis; Phosphopyruvate Hydratase - immunology; Polyethylene Glycols - chemistry; Tumors; Chemical analysis; Electrochemical method; Nanoparticle; Lung cancer; Voltammetry; Monoclonal antibody; Probe; Immunosensor; Hydrochloric acid; Molecules; Tissue; Reduction; Signal; Dynamics; Diagnosis; Human; Disposable; Ethylene glycol; Gold; Lung disease; Polyethylene; Sample; Use; Marker; Malignant tumor; Chemical sensor; Antigen; Neuron; Biosensor; Detection; Glycol; Cancer; Square wave
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac1001959

The development of rapid and sensitive methods for the detection of immunogenic tumor-associated antigen is important not only for understanding their roles in cancer immunology but also for the development of clinical diagnostics. α-Enolase (ENO1), a p48 molecule, is widely distributed in a variety of tissues, whereas γ-enolase (ENO2) and β-enolase (ENO3) are found exclusively in neuron/neuroendocrine and muscle tissues, respectively. Because ENO1 has been correlated with small cell lung cancer, nonsmall cell lung cancer, and head and neck cancer, it can be used as a potential diagnostic marker for lung cancer. In this study, we developed a simple, yet novel and sensitive, electrochemical sandwich immunosensor for the detection of ENO1; it operates through physisorption of anti-ENO1 monoclonal antibody on polyethylene glycol-modified disposable screen-printed electrode as the detection platform, with polyclonal secondary anti-ENO1-tagged, gold nanoparticle (AuNP) congregates as electrochemical signal probes. The immunorecognition of the sample ENO1 by the congregated AuNP@antibody occurred on the surface of the electrodes; the electrochemical signal from the bound AuNP congregates was obtained after oxidizing them in 0.1 M HCl at 1.2 V for 120 s, followed by the reduction of AuCl4− in square wave voltammetry (SWV) mode. The resulting sigmoidally shaped dose−response curves possessed a linear dynamic working range from 10−8 to 10−12 g/mL. This AuNP congregate-based assay provides an amplification approach for detecting ENO1 at trace levels, leading to a detection limit as low as 11.9 fg (equivalent to 5 μL of a 2.38 pg/mL solution).